The Interfaces Lab aims to understand and develop thin-film materials that can improve next-generation optoelectronic devices and integrated circuits.

Our focus lies on the dynamics of charge carriers in metal-dielectric and dielectric-semiconductor interfaces. Such interfaces are fundamental to the operation of most electronic devices, from simple diodes and solar cells to complex 2D field effect transistors and memories. We explore a range of functional thin-film materials, which can serve as a platform for tailoring and controlling semiconductor devices. Most notoriously we work in materials that can improve the conversion efficiency of photovoltaic devices. It is our aim to promote the uptake of solar electricity generation throughout the world and in this way contribute to the mitigation of climate change. 

This young group was established in 2019 by Dr Ruy Sebastian Bonilla. It brings together the world-leading work in photovoltaics carried out by the Semiconductor and Silicon PV group, with a new research area on applied thin-film materials and interfaces. We're also happy to engage in new areas where semiconductor-dielectric interfaces can affect or limit device performance, so please drop us a line if you'd like to collaborate. 

Featured Publications

Extracting band-tail interface state densities from measurements and modelling of space charge layer resistance

Solar Energy Materials and Solar Cells, 2021 (Top Silicon PV conference contribution)

Here we describe a new method to estimate the interface state density at band tails in dielectric-semiconductor interfaces. For this we use sheet resistance measurements and TCAD predictions of conductivity in space charge layers.


Unravelling the silicon-silicon dioxide interface under different operating conditions

Solar Energy Materials and Solar Cells, 2021

Here we investigate the recombination at the Si-SiO2 interface by varying temperature, injection-level, and dielectric charge. Using the extended Shockley-Read-Hall recombination model we provide the first report of the interface defect parameters as a funciton of temperature, including an observation of temperature-dependence in the capture cross-sections.

solmat2021 tsrv

Optoelectronic properties of ultrathin ALD silicon nitride and its potential as a hole-selective nanolayer for high efficiency solar cells

APL Materials, 2020

This work reports the first account of silicon nitride (SiNx) nanolayers with electronic properties suitable for effective hole-selective contacts. We use x-ray photoemission methods to investigate ultra-thin ALD grown SiNx, and we find that the band alignment determined at the SiNx/Si interface favors hole transport.



Assessing the Potential of Inversion Layer Solar Cells Based on Highly Charged Dielectric Nanolayers

physica status solidi (RRL) – Rapid Research Letters, 2021

In this work we study the production and performance of inversion layer silicon solar cells. An ion‐injection technique is used to obtain highly charged dielectric nanolayers, with charge densities as high as 2 × 1013 cm−2. On the basis of such high chage, an efficiency of 24.8% on 10 Ω cm silicon substrates is predicted. Better performance is expected with enhanced passivation, higher charge densities, and optimal negative charge at rear dielectric.


Imaging and quantifying carrier collection in silicon solar cells: A submicron study using electron beam induced current

Solar Energy, 2020

Here we use EBIC to provide insights into the characteristics of PV devices in submicron scales. Imaging and quantification of laser damage is shown on PERC selective emitters, and the effect of laser damage quantified via simulations are shown to reduce 0.12% absolute efficiency of PERC cells.


Charge fluctuations at the Si–SiO2 interface and its effect on surface recombination in solar cells

Solar Energy Materials and Solar Cells, 2020

This work presents a  detailed examination of  how charge at  or near the Si–SiO2 interface influences the performance of silicon solar cells. SiO2 will continue to play a  major role in the development of photovoltaic devices.